1 /***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
9 *
10 * This software is licensed as described in the file COPYING, which
11 * you should have received as part of this distribution. The terms
12 * are also available at https://curl.se/docs/copyright.html.
13 *
14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
15 * copies of the Software, and permit persons to whom the Software is
16 * furnished to do so, under the terms of the COPYING file.
17 *
18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19 * KIND, either express or implied.
20 *
21 * SPDX-License-Identifier: curl
22 *
23 ***************************************************************************/
24
25 /* <DESC>
26 * Send SMTP email using implicit SSL
27 * </DESC>
28 */
29
30 #include <stdio.h>
31 #include <string.h>
32 #include <curl/curl.h>
33
34 /* This is a simple example showing how to send mail using libcurl's SMTP
35 * capabilities. It builds on the smtp-mail.c example to add authentication
36 * and, more importantly, transport security to protect the authentication
37 * details from being snooped.
38 *
39 * Note that this example requires libcurl 7.20.0 or above.
40 */
41
42 #define FROM_MAIL "<sender@example.com>"
43 #define TO_MAIL "<recipient@example.com>"
44 #define CC_MAIL "<info@example.com>"
45
46 static const char *payload_text =
47 "Date: Mon, 29 Nov 2010 21:54:29 +1100\r\n"
48 "To: " TO_MAIL "\r\n"
49 "From: " FROM_MAIL "\r\n"
50 "Cc: " CC_MAIL "\r\n"
51 "Message-ID: <dcd7cb36-11db-487a-9f3a-e652a9458efd@"
52 "rfcpedant.example.org>\r\n"
53 "Subject: SMTP example message\r\n"
54 "\r\n" /* empty line to divide headers from body, see RFC 5322 */
55 "The body of the message starts here.\r\n"
56 "\r\n"
57 "It could be a lot of lines, could be MIME encoded, whatever.\r\n"
58 "Check RFC 5322.\r\n";
59
60 struct upload_status {
61 size_t bytes_read;
62 };
63
payload_source(char * ptr,size_t size,size_t nmemb,void * userp)64 static size_t payload_source(char *ptr, size_t size, size_t nmemb, void *userp)
65 {
66 struct upload_status *upload_ctx = (struct upload_status *)userp;
67 const char *data;
68 size_t room = size * nmemb;
69
70 if((size == 0) || (nmemb == 0) || ((size*nmemb) < 1)) {
71 return 0;
72 }
73
74 data = &payload_text[upload_ctx->bytes_read];
75
76 if(data) {
77 size_t len = strlen(data);
78 if(room < len)
79 len = room;
80 memcpy(ptr, data, len);
81 upload_ctx->bytes_read += len;
82
83 return len;
84 }
85
86 return 0;
87 }
88
main(void)89 int main(void)
90 {
91 CURL *curl;
92 CURLcode res = CURLE_OK;
93 struct curl_slist *recipients = NULL;
94 struct upload_status upload_ctx = { 0 };
95
96 curl = curl_easy_init();
97 if(curl) {
98 /* Set username and password */
99 curl_easy_setopt(curl, CURLOPT_USERNAME, "user");
100 curl_easy_setopt(curl, CURLOPT_PASSWORD, "secret");
101
102 /* This is the URL for your mailserver. Note the use of smtps:// rather
103 * than smtp:// to request a SSL based connection. */
104 curl_easy_setopt(curl, CURLOPT_URL, "smtps://mainserver.example.net");
105
106 /* If you want to connect to a site who is not using a certificate that is
107 * signed by one of the certs in the CA bundle you have, you can skip the
108 * verification of the server's certificate. This makes the connection
109 * A LOT LESS SECURE.
110 *
111 * If you have a CA cert for the server stored someplace else than in the
112 * default bundle, then the CURLOPT_CAPATH option might come handy for
113 * you. */
114 #ifdef SKIP_PEER_VERIFICATION
115 curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
116 #endif
117
118 /* If the site you are connecting to uses a different host name that what
119 * they have mentioned in their server certificate's commonName (or
120 * subjectAltName) fields, libcurl refuses to connect. You can skip this
121 * check, but it makes the connection insecure. */
122 #ifdef SKIP_HOSTNAME_VERIFICATION
123 curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);
124 #endif
125
126 /* Note that this option is not strictly required, omitting it results in
127 * libcurl sending the MAIL FROM command with empty sender data. All
128 * autoresponses should have an empty reverse-path, and should be directed
129 * to the address in the reverse-path which triggered them. Otherwise,
130 * they could cause an endless loop. See RFC 5321 Section 4.5.5 for more
131 * details.
132 */
133 curl_easy_setopt(curl, CURLOPT_MAIL_FROM, FROM_MAIL);
134
135 /* Add two recipients, in this particular case they correspond to the
136 * To: and Cc: addressees in the header, but they could be any kind of
137 * recipient. */
138 recipients = curl_slist_append(recipients, TO_MAIL);
139 recipients = curl_slist_append(recipients, CC_MAIL);
140 curl_easy_setopt(curl, CURLOPT_MAIL_RCPT, recipients);
141
142 /* We are using a callback function to specify the payload (the headers and
143 * body of the message). You could just use the CURLOPT_READDATA option to
144 * specify a FILE pointer to read from. */
145 curl_easy_setopt(curl, CURLOPT_READFUNCTION, payload_source);
146 curl_easy_setopt(curl, CURLOPT_READDATA, &upload_ctx);
147 curl_easy_setopt(curl, CURLOPT_UPLOAD, 1L);
148
149 /* Since the traffic is encrypted, it is useful to turn on debug
150 * information within libcurl to see what is happening during the
151 * transfer */
152 curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
153
154 /* Send the message */
155 res = curl_easy_perform(curl);
156
157 /* Check for errors */
158 if(res != CURLE_OK)
159 fprintf(stderr, "curl_easy_perform() failed: %s\n",
160 curl_easy_strerror(res));
161
162 /* Free the list of recipients */
163 curl_slist_free_all(recipients);
164
165 /* Always cleanup */
166 curl_easy_cleanup(curl);
167 }
168
169 return (int)res;
170 }
171
